Embodiments of the present invention exemplarily described herein relate generally to methods and apparatuses for processing workpieces. More particularly, embodiments of the present invention exemplarily described herein relate to methods and apparatuses for processing workpieces in which light is directed onto one side of a processed workpiece and the light is detected on another side of the workpiece.
Within the semiconductor industry, substrate dicing is a critical aspect of package assembly that facilitates all subsequent operations in an assembly process. Dicing is conventionally performed using a mechanical saw. The thickness of the semiconductor substrates (typically formed of silicon) can be reduced to enable through-silicon via (TSVs), stacked memory, interposer, micro electro-mechanical (MEM), and system-in-package (SIP) technologies. However when reduced in thickness to below about 50 μm, the substrate becomes increasingly flexible, fragile and difficult to dice by traditional mechanical dicing techniques. Laser-based dicing techniques, which use laser light to remove substrate material by ablation, have been developed to address shortcomings of traditional mechanical dicing. Nevertheless, it can be difficult ensure that the right amount of material is removed to dice the substrate. If too much laser energy is applied to an area of the substrate, the laser may damage supporting structures such as a die-attach-film (DAF), a chuck, and the like. If too little laser energy is applied, the substrate will not be diced.